A method and apparatus is provided for determining physical uplink channel power control parameter values for use after a beam failure recovery. A physical random access channel with a spatial domain transmission filter associated with a selected downlink reference signal from a set of downlink reference signals configured for a link recovery is transmitted. A determination is made as to whether the selected downlink reference signal is configured for at least one of a set of uplink spatial relation configurations as a reference signal for an uplink spatial relation setting for a physical uplink channel transmission. A power control parameter value for the physical uplink channel transmission is determined. The physical uplink channel is transmitted with the spatial domain transmission filter associated with the selected downlink reference signal and the determined physical uplink channel power control parameter value.
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2. The method in accordance with claim 1, wherein the user equipment transmits the physical uplink channel with the same spatial domain transmission filter as that used for reception of the selected downlink reference signal.
3. The method in accordance with claim 1, wherein determining of the default power control parameter value by the user equipment for the physical uplink channel transmission in response to determining the selected downlink reference signal is not configured for any of the set of uplink spatial relation configurations includes determining by the user equipment a value for a user equipment specific open loop physical uplink channel power control parameter.
4. The method in accordance with claim 3, wherein as part of determining the default power control parameter value for the user equipment specific open loop physical uplink channel power control parameter includes setting by the user equipment the value of the user equipment specific open loop physical uplink channel power control parameter to zero and using a physical uplink channel closed loop power control adjustment state with a lowest index value.
5. The method in accordance with claim 1, wherein receiving the activation of the uplink spatial relation configuration by the user equipment includes receipt of the activation by higher layers, where the higher layers include a medium access control layer and the activation being received by the user equipment in a medium access control-control element layer.
6. The method in accordance with claim 1, wherein receiving the reconfiguration of the uplink spatial relation configuration by the user equipment includes receiving by the user equipment the reconfiguration of a spatialRelationInfoToAddModList parameter configured by higher layers.
7. The method in accordance with claim 6, wherein the higher layer includes at least one of a medium access control layer and a radio resource control layer.
8. The method in accordance with claim 1, wherein the physical uplink channel is a physical uplink shared channel, and each of a set of sounding reference signal resources is associated with one of the set of uplink spatial relation configurations and maps to an SRI-PUSCHPowerControl configuration.
9. The method in accordance with claim 1, wherein the physical uplink channel is a physical uplink control channel, and the set of uplink spatial relation configurations is a set of physical uplink control channel spatial relation info configurations.
10. The method in accordance with claim 1, wherein determining the power control parameter value for the physical uplink channel transmission by the user equipment in response to determining the selected downlink reference signal is configured for at least one of the set of uplink spatial relation configurations includes determining by the user equipment a value for a user equipment specific open loop physical uplink channel power control parameter corresponding to an uplink spatial relation configuration of the at least one of the set of uplink spatial relation configurations.
11. The method in accordance with claim 10, wherein as part of determining the power control parameter value for the user equipment specific open loop physical uplink channel power control parameter by the user equipment includes determining by the user equipment a physical uplink channel closed loop power control adjustment state and a pathloss reference signal corresponding to the uplink spatial relation configuration of the at least one of the set of uplink spatial relation configurations.
12. The method in accordance with claim 11, wherein after receiving the physical random access channel, and upon transmitting a response message by the network entity, the user equipment resets all configured physical uplink channel closed-loop power control adjustment states except for the determined physical uplink channel closed-loop power control adjustment state.
13. The method in accordance with claim 1, wherein the selected downlink reference signal includes a synchronization signal/physical broadcast channel block as a reference signal for the uplink spatial relation setting, and the selected downlink reference signal used by the user equipment for physical random access channel resource selection.
This invention relates to wireless communication systems, specifically methods for configuring downlink reference signals to assist user equipment (UE) in uplink spatial relation settings and physical random access channel (PRACH) resource selection. The problem addressed is the need for efficient and reliable reference signal selection to optimize uplink transmissions and random access procedures in wireless networks. The method involves selecting a downlink reference signal, such as a synchronization signal/physical broadcast channel (SSB) block, to serve as a reference for uplink spatial relation settings. This reference signal helps the UE determine the optimal spatial parameters for uplink transmissions, ensuring proper beam alignment and signal quality. Additionally, the same downlink reference signal is used by the UE to select appropriate PRACH resources, which are critical for initiating communication with the network. By using a single reference signal for both purposes, the method reduces complexity and improves coordination between uplink spatial configuration and random access procedures. This approach enhances system efficiency and reliability, particularly in scenarios with dynamic channel conditions or beamforming requirements.
14. The method in accordance with claim 1, wherein the selected downlink reference signal includes a channel state information-reference signal as a reference signal for the uplink spatial relation setting, and the selected downlink reference signal used by the user equipment for physical random access channel resource selection.
15. The method in accordance with claim 1, wherein in response to determining the selected downlink reference signal is configured for more than one of the set of the uplink spatial relation configurations by the user equipment, the user equipment uses the values for the power control parameters included in the uplink spatial relation configuration with the lowest uplink spatial relation index.
In wireless communication systems, user equipment (UE) must manage uplink transmissions efficiently, particularly when multiple spatial relation configurations are available for a downlink reference signal. The problem arises when a downlink reference signal is configured for more than one uplink spatial relation configuration, leading to ambiguity in selecting the appropriate power control parameters. This ambiguity can degrade communication performance by causing misalignment in transmission power and spatial direction. To address this, a method ensures that when a downlink reference signal is linked to multiple uplink spatial relation configurations, the UE selects the configuration with the lowest uplink spatial relation index. This selection process standardizes the choice of power control parameters, ensuring consistent and predictable uplink transmission behavior. The method involves the UE determining the applicable configurations, identifying the lowest index among them, and applying the corresponding power control parameters. This approach simplifies the decision-making process for the UE, reducing complexity and improving reliability in uplink transmissions. By standardizing the selection criteria, the method enhances system efficiency and minimizes potential conflicts in spatial relation configurations.
16. The method in accordance with claim 15, wherein the more than one of the set of uplink spatial relation configurations are respectively associated with different service/traffic types.
This invention relates to wireless communication systems, specifically to methods for managing uplink spatial relation configurations in a network. The problem addressed is the inefficient use of spatial relations in uplink transmissions, which can lead to suboptimal performance and resource utilization. The invention provides a solution by dynamically associating multiple uplink spatial relation configurations with different service or traffic types, allowing the network to optimize transmission based on the specific requirements of each service. The method involves configuring a user equipment (UE) with a set of uplink spatial relation configurations, where each configuration defines a spatial relationship between the UE and a network node for uplink transmissions. The key improvement is that different configurations within the set are associated with different service or traffic types, such as enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), or massive machine-type communication (mMTC). This allows the UE to select or apply the most appropriate spatial relation configuration based on the type of service or traffic being transmitted, ensuring better performance and resource efficiency. By dynamically adjusting the spatial relation configurations for different traffic types, the invention enables more efficient use of network resources, reduces interference, and improves overall system performance. The solution is particularly useful in scenarios where multiple services with varying requirements coexist in the same network.
17. The method in accordance with claim 1, wherein the selected downlink reference signal is a reference signal of another serving cell different than a current serving cell used for physical random access channel resource selection, and determining by the user equipment whether the selected downlink reference signal is configured for at least one of a set of the uplink spatial relation configurations comprises determining by the user equipment whether both the value of a serving cell index and the selected downlink reference signal are configured for at least one of a set of uplink spatial relation configurations.
18. The method in accordance with claim 1, wherein during the link recovery, while in a connected mode, if the user equipment is not configured with any of the at least one of a set of uplink spatial relation configurations, then the user equipment determines the default power control parameter value for a user equipment specific open loop physical uplink channel power control parameter as the parameter value associated with a lowest index of a set of user equipment specific open loop physical uplink channel power control parameter values.
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March 22, 2021
October 4, 2022
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